There is an electronic device including a rack, a mount housing mounted in the rack, and a cooling fan for cooling the inside of the mount housing (see, for example, Japanese Laid-open Patent Publication No. 2005-286268 and International Publication Pamphlet No. WO2009/004708). The mount housing houses multiple plug-in units each equipped with multiple electronic components that generate heat, for example.
In this kind of electronic device, the cooling fan operates to generate cooling air passing through the mount housing in the front-rear direction. This cooling air is introduced into the plug-in units from inlets on the front side of the plug-in units, for example. The cooling air introduced into the plug-in units is discharged from outlets on the rear side of the plug-in units after passing over the multiple electronic components. The cooling air cools the electronic components in the respective plug-in units.